1. Field of the Invention
The present invention relates to a modular, easy-to-assemble, tapered, hollow reamer for medical applications; and more particularly, to a modular, tapered, hollow reamer that is inexpensive to produce and has a disposable reamer assembly, which can be attached to a reusable shaft portion and includes one or more bone debris capturing cavities.
2. Description of the Prior Art
Reaming of the internal canal of bones is required in many surgical procedures of orthopedic surgery. These procedures include hip replacement, knee replacement and shoulder replacement. Reamers are also used in procedures that involve the internal fixation of fractures. Prior art reamers typically fall into two major classes: rigid and flexible shaft. Typically, reaming of the internal bone canal is achieved through utilization of a solid cylindrical or tapered reamer. Solid cylindrical or tapered reamers currently utilized are required to cut both cancellous bone (spongy bone) and cortical bone (hard bone). Cortical bone is generally denser and stronger, requiring an efficient cutter to machine the canal for a proper fit of the implant. Conventional reamers can cut cortical bone initially but can quickly dull after a single use, or at best a few uses. Once the reamer acquires dull cutting edges, its bone cutting efficiency is substantially reduced. In such cases the reamer can generate sufficient friction/heat to damage or kill the surrounding bone. These prior art solid cylindrical or tapered reamers are intended for multiple uses and therefore become less efficient after each surgery, resulting in poor cutting performance and bone necrosis. Dull reamer blades can also incorporate bone debris or bone cement debris into the living bone tissue, creating bone healing problems.
U.S. Pat. No. 4,116,200 to Braun et al. discloses a milling tool for surgical purposes. The surgical milling tool is a hand-operated milling machine for milling the heads or sockets of bone joints and has a spherical shape. The tool is formed of a hemispherical cup integrally formed with a cylindrical skirt and flange and is provided with a plurality of openings of semi-oval shape, each having a cutting edge arranged at the minor axis of the oval shape. The openings are situated such that, upon rotation of the cup, the cutting edges thereof overlap to provide a continuous cutting edge surface conforming generally to the shape of the cup. The hemispherical shape of the cup provides the ability to hollow out the arcuate shape of the bone joints. Bone and cartilage shavings are formed during the milling process and are collected in a border area inside of the hemispherical cup. The surgical milling tool is provided for multiple uses and therefore the tool will become less efficient after each surgery, resulting in poor cutting performance and bone necrosis. Moreover, the spherically shaped reaming tool is not tapered.
U.S. Pat. No. 5,190,548 to Davis discloses surgical reamer. This surgical bone reamer includes a rotatable, elongated shank having a proximal end, a distal end and a longitudinal axis. A reaming head mounted on the distal end. A plurality of equally spaced walls is radially disposed on the reaming head around the longitudinal axis. Tip edges for penetrating bone are defined on the radial walls to be disposed angularly with the longitudinal axis. Reaming edges joined to the tip edges extend longitudinally from the tip edges in the proximal direction parallel to and an equal radial distance from the longitudinal axis for reaming a cylindrical tunnel when the reaming head is rotated in bone. Tapered flutes disposed angularly between the tip edges and the radial walls permit bone to be evacuated through the reaming head when forming a tunnel in bone. The reaming head is provided with angular tips and edges for penetrating the bone and is thus not a single use disposable cutter. The debris created is not stored away from the cutting edge and thus previously cut material may be included in the bone.
U.S. Pat. No. 5,549,613 to Goble et al. discloses a modular surgical drill. This modular surgical drill is in the form of a rigid drill shaft and a drill bit, which are connected together by a tongue-and-groove arrangement attaching the rear end of the drill bit to the forward end of the drill shaft. Each of the shaft and drill bit are provided with through bores extending centrally through their entire length. These bores become aligned upon assembly of the drill bit and shaft. The modular drill is intended to be employed with a guidewire for drilling holes into bone. The assembled drill bit and shaft are placed on the guidewire and moved down such guidewire into contact with the bone, whereupon a tunnel may be formed into the bone by rotating and advancing the drill bit along the guidewire. The dimensions of the bore and guidewire are so selected as to prevent the drill bit and drill shaft from moving relative to one another once they are assembled and mounted on the guidewire. Debris created during drilling is not removed and collected away from the cutting location. The central bore is solid and as such does not receive cut bone debris. The cutter used is not disposable.
U.S. Pat. No. 5,556,399 to Huebner discloses a bone-harvesting drill apparatus and method for its use. A coring drill harvests bone from a donor area of the human body. The drill bit is formed with a cylindrical, hollow shaft and a half-conical tip or cutting head. The cutting head is provided with a sharpened edge, which meets at an apex with a non-sharpened edge, forming an obtuse angle of approximately 120 degrees. The sharpened edge is configured to cut into bone when the drill bit is rotated in a clockwise direction. With the apex directed against a section of bone, the cutting edge sheers off fragments of bone, which are then drawn upwardly through the hollow shank of the drill bit. As the drill bit is forced downwardly, continuous cutting action occurs and the morselized bone can then be removed from the shank and used to build-up bone in other areas to which it is transplanted. The drill bit fittingly mates on the distal end a fitting that renders the drill bit physically compatible with a conventional chuck. The bit includes a pair of diametrically opposed, oppositely inclined recesses that cooperate with a crossbar member within a bit-receiving bore of the fitting. When the aligned drill bit is pressed into the fitting, the crossbar member cams along the inclined recesses causing the bit to rotate relative to the fitting. The resulting frictional engagement between the recesses and the crossbar member, along with a detent assembly between the bit and the fitting, securely lock the bit onto the distal end of the fitting, yet render removal possible by the use of a removal tool. The bone harvesting tool provides a non-disposable cutter. Reuse of the cutter dulls the beveled lip edges. Moreover, the harvested bone collection central bore requires a thorough cleaning prior to each use, creating contamination possibilities.
U.S. Pat. No. 5,690,634 to Muller et al. discloses a medullary drill head. This drill head for intramedullary drilling has a front part, a middle part and a rear part and is shaped as a hollow body of revolution. The front and rear parts have spiral slots formed with cutting edges. The rear part has an attachment for coupling to a drilling shaft. The drill head is not disposable, and as a result, the drill head is continuously reused, resulting in dulling of the cutting edges. Moreover, the drill head includes three openings in the form of spirally shaped slots configured to have cutting edges similar to a grater; and has no place to collect bone debris.
U.S. Pat. No. 5,954,671 to O'Neill discloses a bone harvesting method and apparatus. This apparatus and method harvests bone using a manual, cylindrical, multi-directional coring device with a guided delivery system that can be inserted through a percutaneous or closed approach to extract precisely measured amounts of bone or bone marrow. A series of guide wires, obturators, dilators and cannulas are used as the exposure and delivery instrumentation for a cutting tool. The cutting tool has a tip with six cutting edges for cutting in all directions. This apparatus is a manual, cylindrical, multi-directional coring device with a guided delivery system to extract precisely measured amounts of bone or bone marrow. The cutter portion of the device is not disposable and is subject to wear and dull edges. This coring device does not suggest a tapered reamer.
U.S. Pat. No. 5,976,144 to Fishbein et al. discloses a hollow dome reamer with removable teeth. This surgical reamer has a hollow dome with apertures spaced apart arranged in arcs extending from an apex of the dome to the base portion of the dome, and removable teeth positioned in the apertures. Each cutting tooth has (i) a flange that is aligned flush with the external surface of the dome, (ii) a raised cutting edge extending above the flange and the external surface of the dome, and (iii) an interior passageway communicating between the outside and inside of the dome. A base plate may be removably secured on the base portion of the dome to provide closure for the central cavity of the dome. Although the teeth are removable, they are not disposable in nature; the teeth are removed for replacement or for re-sharpening and are used again. Removal of the small teeth may be cumbersome and difficult, and may even pose a danger during removal as the person removing the teeth may be cut by the sharp edges; replacement of the teeth into the apertures of the reamer will likely pose the same problems. The bone debris is not collected away from the cutting edges of the teeth. This hollow domed reamer is spherically shaped reamer; does not suggest a tapered reamer.
U.S. Pat. No. 5,980,170 to Salyer discloses a tool driver. This tool driver has a shaft with a longitudinal axis and opposite ends. A boss is secured at one of the shaft ends by which the tool driver is connected to a rotary tool. A tool collate is secured at the other of the shaft ends by which the tool driver may be driven by a surgical hand piece having a chuck in which the collate may be positioned. The boss has a distal end surface with a groove therein. Both the groove and the distal end surface extend transversely of the axis. A pin is positioned in the groove on the axis. A latch mechanism is provided to hold a mounting bar of a rotary tool in the groove on the pin, whereby the rotary tool is held exactly coaxially of the driver during use. The rotary tool, which is used with the driver has a bar containing the same dimensions as the groove in the boss of the tool driver. The bar thus fills and is complementary to the slot. The bar has a hole therein which is complementary to the pin. The pin extends coaxially of the shaft and the boss. The bar hole in which the pin of the tool driver is positioned is precisely coaxial of the axis of the tool about which the cutting edges are precisely positioned. The cutters are connected to the tip of the shaft and are spherical in nature for joint and patella reaming. In addition, the reamer cups are not disposable in nature. The bone fragments are not collected and kept away from the cutting edge. This spherically shaped reamer is not tapered.
U.S. Pat. No. 6,193,722 to Zech et al. discloses a hollow milling tool. The hollow milling tool produces substantially hollow cylindrical depressions in human or animal tissue. It also produces tissue pillars, which are removed at a harvest location, transported to a defect location and implanted. The hollow milling tool has teeth for the ablation of tissue which are arranged at the distal end of the milling tool at the end side. Furthermore, the milling tool has passages for transporting a cooling fluid to a cooling region of the milling tool lying near the distal end during the ablation of tissue. Teeth are constructed within the milling tool for accomplishing the depressions. These teeth will eventually need sharpening as the tool is used over time. No structure is contained within the '722 patent that discloses or suggests a tapered reamer.
U.S. Pat. No. 6,332,886 to Green et al. discloses a surgical reamer and method of using same. This device is used for expedited reaming of a medullary canal. The device includes a reamer head connected at the distal end of a rotatable drive shaft. The reamer head has a cutting head with five blades and flutes therebetween. Each blade has a front cutting portion. The blades can also include a side cutting portion. The method for removing material from the medullary canal of a bone includes the steps of reaming an area of the medullary canal to remove material; irrigating the material to be removed while reaming to reduce generation of heat and move removed material from the reaming area; and aspirating the removed material while reaming to create a negative intramedullary canal pressure to assist in the removal of the material. The blades and flutes at the reamer are reused and are subject to dulling. The bone chips are to be removed by the irrigating fluid, which means they are always present adjacent to the cutting portions and may be forced into the bone tissue. No disclosure in the '886 patent suggests a tapered reamer.
U.S. Pat. No. 6,451,023 to Salazar et al. discloses a guide bushing for a coring reamer, a storage package for reamer assembly, and a method of use. This guide bushing for a coring reamer has a tapered member with its largest diameter at its first end so that the guide bushing frictionally engages an internal surface of the reamer with a line contact. The guide bushing has a passage sized to slidably receive a guide pin. In use, the bushing advances in the proximal direction within the coring reamer along a guide pin while the excavated bone enters the passageway through the reamer. A storage package specifically designed for the reamer assembly is employed to remove the excavated bone from within the reamer. The package has a closed distal end and an open proximal end closeable with a cap. With the coring reamer received in cantilevered fashion through a central opening of the cap of the tube, and with an adapter that couples the coring reamer to a handpiece installed, a wrench is placed over the adapter and turned while the user grips peripheral surfaces of the cap to prevent rotation of the coring reamer. A plunger is inserted through the opening and through the coring reamer from the proximal end. The plunger is pushed through the reamer until the bone core and bushing fall out of the distal end of the coring reamer. The guide bushing for a coring reamer is appointed with an open end surrounded by peripheral teeth. The teeth are arranged peripheral to the body of the tube of the reamer. The tube is hollow and therefore excavated bone accumulates therewithin. The reamer, bushing and packaging are disposed of after use. The '023 patent discloses a bone excavating tool that does not prepare a bone canal for implantation of femoral implants. No structure is disclosed therein that suggests a tapered reamer.
U.S. Pat. No. 7,074,224 to Daniels et al. discloses a modular tapered reamer for bone preparation and associated method. This kit is for use in performing joint arthroplasty and includes a trial and a reamer. The reamer is said to be useful when preparing a cavity in the intramedullary canal of a long bone with the use of a driver, and to assist in performing a trial reduction. The reamer includes a first portion for placement at least partially in the cavity of the long bone and a second portion operably connected to the first portion. The reamer is removably connected to the driver to rotate the reamer. The trial is removably attachable to the reamer. This tapered reamer is not disposable and does not have provision for accumulating bone debris away from the cutting portion of the bone.
U.S. Patent Application Publication No. 2005/0113836 to Lozier et al. discloses an expandable reamer. This expandable reamer includes a cannulated shaft and a plurality of straight cutting blades having deformable points. The blades are hingably outwardly rotatable at the deformation points between a contracted position and an expanded position. In the contracted position, the blades are substantially parallel to the longitudinal axis of the cannulated shaft and, in the expanded position, the blades have at least a portion oriented radially outward from the longitudinal axis, thereby forming a larger diameter cutting surface in the expanded position and in the contracted position. The blades are formed from a portion of the cannulated shaft by, e.g. milling longitudinally extending slots through the wall of the cannulated shaft. The slots serve as flutes dividing the cutting edge and trailing edge of each adjacent blade. Each blade may also include more than one segment arranged along its length, the segments being coupled by deformation points. The expandable reamer may be used for cutting a cavity in a bone or other structure that is larger than the diameter of the entry point into the bone and greater than the diameter of the contracted reamer. The expandable reamer is not disposable. Since the expandable blades are deformably attached to the cannulated shaft, the cut bone debris is not collected away from the bone cutting region. As a result, fragments of cut bone debris may be pushed into the bone tissue by the deformable rotating blades.
U.S. Patent Application Publication No. 2006/0004371 to Williams et al. discloses an orthopedic reamer. This orthopedic reamer is for use in creating and sizing canals in a bone. The orthopedic reamer includes a non-polymeric cutting portion having at least one cutting surface thereon and a polymeric body portion covering at least a portion of the cutting portion. The at least one cutting surface is not covered by the polymeric body portion. The orthopedic reamer provides cutting components including a blade or saw like construction, rather than the plurality of teeth. Although the orthopedic reamer is appointed for disposability, the publication requires that the entire reamer, and not just the cutting portion, be disposed of. That is to say, the entire reamer, including the non-polymeric cutting portion and the polymeric body portion of the device are all disposed of; not just the cutter.
There remains a need in the art for a low cost, modular, easy-to-assemble, hollow tapered reamer for medical applications having a disposable hollow cutter assembly. Also needed in the art is a disposable hollow cutter assembly of the type described, which can be attached to a reusable shaft portion that provides means for reaming of the internal canal of bones. Further needed in the art is a cutter assembly having means for collecting bone debris and keeping the collected debris displaced from the cutting edges, so that the cutting edges remain during drilling and after one use of the reamer a new hollow cutter assembly can be utilized, and the old hollow cutter assembly can be discarded.